<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="../bootstrap-5.1.3-dist/css/bootstrap.css">
    <script src="../bootstrap-5.1.3-dist/js/bootstrap.bundle.js"></script>
</head>

<body class="container">
    <h3 align="center">向上展开菜单</h3><br /><br /><br /><br /><br />
    <div class="dropup">
        <button class="btn btn-secondary dropdown-toggle" data-bs-toggle="dropdown" type="button">箱包皮具</button>
        <div class="dropdown-menu">
            <a class="dropdown-item" href="#">旅行箱包</a>
            <button class="dropdown-item" type="button">精品男包</button>
            <a class="dropdown-item" href="#">潮流女包</a>
            <button class="dropdown-item" type="button">精品皮带</button>
        </div>
    </div>
</body>

</html>

</html>